SelectFilter unique/distinct relationship value
I have a table of tickets that belong to a location. Some locations are in the same city. How can I use a SelectFilter to get a unique list of cities from the locations table to filter the tickets? This is my code so far:
But this gives me a list of duplicated cities. I tried something like the following but unsuccessfully:
Not sure how to achieve this?
But this gives me a list of duplicated cities. I tried something like the following but unsuccessfully:
Not sure how to achieve this?
